Purple bacteria 'batteries' turn sewage into clean energy

Purple phototrophic bacteria -- which can store energy from light. when supplied with an electric current can recover near to 100 percent of carbon from any type of organic waste, while generating hydrogen gas for use as fuel. Organic compounds in household sewage and industrial wastewater are a rich potential source of energy, bioplastics and even proteins for animal feed -- but with no efficient extraction method, treatment plants discard them as contaminants. Now researchers have found an environmentally-friendly and cost-effective solution.